There is already an opensource alternative to Obsidian, its name is #Logseq, you have mobile and desktop app

The MM-DD format, as a euro, pisses me off. I use YYYY-MM-DD though. It’s the recomended format by ISO, and it allows me to name files with that format and sort by name.

I really hope so, it should be taught, because for me it was a slow learning process. First I started using Obsidian, and moving all my notes from Evernote, Notion, and others manually. After that I moved to Logseq, which is like Obsidian but open-source. And the last step was using an open-source syncing tool (Syncthing) to have my notes synced locally in all devices. And now I have been 2 years self-hosting my notes in a really easy way.